The Low Cost Attitude Position Sensor utilizes the earth's electrostatic field to determine the roll position of small, highly maneuverable missiles or guided projectiles moving at supersonic speeds.
Previous methods of measuring the roll of guided missiles and projectiles consist of using optical techniques such as sunlight, flares or lasers or of using mechanical methods such as vyros and gyros. The optical means of measuring roll obviously depends on a repeatable source of light intensity such as the sun. This, therefore, eliminates from testing those days when it is raining or there exists a heavy cloud cover, or at night.
The gyros and vyros are the usual methods utilized to determine roll because they are independent of weather conditions. However, they are quite expensive, require a fairly large volume, and as of yet are unreliable in a high-g (up to 15,000g's) environment. Moreover, in order to get roll position, an integration circuit is required which must have initial conditons. Also, a vehicle which rolls constantly over a given time period requires the accuracy of the mechanical system be very high in order to get accurate roll position towards the end of the flight. This in turn makes this system very expensive.